Do you know if all 10 of your orchids need Intermediate temperatures? If so, 65-70F should be fine. Other indoor variables are light, RH (relative humidity), and air movement. Do you know what each of your orchids needs and if their winter location provides these? If all of them grow in Phal conditions, you're good. As for temperatures, as Jane said, windows can leak cold air. Here in Minnesota, I cover the glass inside with 3M clear plastic film (no financial interest): # Indoor 5-Window Insulator Kit # Insulates five 3 x 5 ft. indoor windows # 62 in. x 210 in. clear film # 1/2 in. x 27.7 yd. tape # Performs like an extra storm window # Shrinks tight for clear-as-glass results # Reduces condensation & stops cold drafts # Helps reduce heating costs & save energy Online, the Mills Fleet Farm price, for example, is $12.79. Other brands may be less expensive. My orchids are in a bedroom. The 4' x 4' windows face E/SE, and putting film on them keeps the room warmer, keeps RH higher, and cuts down on the need for the little space heater. All winter, there's a fan going for air movement, and there's supplemental lighting from an LED and CFLs. For a couple of years, I didn't get around to putting film on, and the orchids didn't do as well the rest of the year. In S. Carolina, the insulation may not be as critical. Hope this helps, WhiteCat8 Here is a link that might be useful: Scotch Indoor 5-Window Insulator Kit

We still have patches of snow from 2 weeks ago in the garden beds and on north sides of roofs. Many mornings are just above 20, certainly below freezing. I'm thinking Mexico! The Spring blooming bulbs are going to wait til it hits 40. Gusty winds took our power last night but it was restored quickly, thankfully. The icy/sleety/snow mix expected overnight just doesn't tickle my fancy at all. I long for the balmy days of 50 degrees and a nice soggy rain to clear the air.

Mmontina, I like the light colour of your sans but it's no 'Moomshine'. It is a Sansevieria trifasciata Futura of some type. I have a Silver Laurenttii and when it pups, they look exactly like Moonshine until it gets a little bigger then the yellow margins show up. They get big and darken with age. Now my Moonshine and I have plenty. Stush

I's good to hear you have a porch to winter store plants imagine if it gets to chilled at night you can simply open a door and share some inside heat or use a suplemental heater for a while With this in mind is it safe to assume your hot house is not attached to your house ? If you have a heater that works for you already I wouldn't suggest adding a lighting system (bulbs) to your hot house as the only sorce of heat simply because they wouldn't be on at night Emphisis on night: It gets to cold to often with colder temps at the minus (?) F degrees bulbs that are off aren't going to warm any area Some bennifits to a heater are it can turn on and off on an as needed basis by thermatic controls and timers helping maintain disired warmth though out the entire day and night. A draw back is loosing power for to long of time with out a second sorce on a colder day On a logical thought, a cold frame wont work for you but if it where to work you wouldn't need any added lighting to keep plants warmer I agree it's better and easier to grow some plants slower if ideal growing conditions cant be suplied with in a persons means if you dont push growth, it's not uncommon for a healthier plant to be seen in the future. Many compliments are read that are directed to Mike Mike Your doing something right